Future flood scenarios in the Paraná and Uruguay Rivers

CAMILLONI, INÉS; SAURRAL, RAMIRO

París, Francia

Workshop; Workshop on metrics and methodologies of estimation of extreme climate events; 2010

WCRP UNESCO GEWEX CLIVAR IHP WRN

The La Plata basin is one of the most densely populated regions of South America. It has a drainage basin that exceeds 3 million km2 and spreads over five South American countries; approximately 46% of its surface is in Brazil, 30% in Argentina, 13% in Paraguay, 7% in Bolivia, and 4% in Uruguay. The water resources of the basin sustain important agricultural activities and hydroelectric plants that provide energy to all the countries that share the basin. The main tributaries of La Plata River are the Paraná and Uruguay Rivers with annual mean discharges of 18000 m3/s and 5000 m3/s respectively. During the last 50 years, large areas along the margins of both rivers were subject to extreme flood events causing considerable damage. The Variable Infiltration Capacity (VIC) hydrological model was used considering regional climate projections of temperature and precipitation derived from a regional climate model for emission scenarios A2 and B2 to quantify changes of frequency and duration of flood events in the margins of the lower sections of the Paraná and Uruguay Rivers during the 21st century. Results show that the number of flood events in the Paraná River by the end of the present century would be three times the cases of the 1990-99 period with an increase also in duration (up to 9 months). The hydrological scenarios of the Uruguay River show an increase in the frequency of flood events that by 2091-2100 almost double the cases of the reference period (1990-99). Due to the cascade of uncertainties associated to the emission scenarios and the climate and hydrological models, results should be considered as first order indicators of the possible future ranges of flood parameters (frequency and duration) in the Paraná and Uruguay Rivers.